Thermal pasteurization may refer to raising water or other fluid temperature to make the water or fluid safe. In the case of water, the water may be safe to drink, for example, after it is pasteurized. The pasteurization may not result in all pathogens being killed or inactivated, but may reduce the pathogen level to a level suitable and/or safe for human consumption. Accordingly, pasteurization processes may not have the same result as sterilization. Moreover, pasteurization processes may not remove particulates or turbidity from water. However, thermal pasteurization, in comparison to other pasteurization processes such as slow/rapid sand filters, chemical treatments, and the use of ultraviolet light, is not negatively impacted by turbidity. This feature makes thermal pasteurization particularly advantageous for water or fluid that may be less than clear.
Thermal pasteurization has been thought of as a batch or flow-through process. In a batch process, water or fluid containers may be heated by burning fuels or by exposure to sunlight. For a flow-through process, the water or fluid may be heated while it passes through a pipe or duct and emerges as pasteurized. Batch processes may be less expensive to manufacture, but they may be more expensive to operate due to the need to bring the system up to a suitable temperature each time a new batch is started.
Inactivation and rates of inactivation of various pathogens vary based on the type of pathogen and, while it is common to bring water to a boil to assure inactivation of pathogens, most pathogens may be inactivated at temperatures below boiling. However, it remains that inactivation rates increase rapidly as temperatures increase.